[P3.284] Long-Term Open-Label Extension (OLE) Study Evaluating USL255, Once-Daily Extended-Release Topiramate, in Patients With Partial Onset Seizures: Interim Analysis From PREVAIL OLE

Toufic A. Fakhoury,1Robert Hogan,2Ilan Blatt,3Steve Chung,4Bob Anders5
1Lexington, KY, USA, 2Saint Louis, MO, USA, 3Tel Hashomer, Israel, 4Phoenix, AZ, USA, 5Maple Grove, MN, USA

OBJECTIVE: Evaluate interim data from a long-term study of USL255, once-daily extended-release topiramate, for the adjunctive treatment of refractory partial-onset seizures (POS).
BACKGROUND: USL255 demonstrated efficacy and favorable safety/tolerability in a double-blind, placebo-controlled, phase 3 study (PREVAIL; NCT01142193). Interim data from the PREVAIL open-label extension (OLE) study (NCT01191086) are presented here.
DESIGN/METHODS: Interim analyses (cutoff date 1 July 2013) of an ongoing OLE study of USL255 in adult patients with POS on 1-3 concomitant AEDs were performed. Patients who completed the 11-week double-blind phase from PREVAIL were eligible to enroll in the OLE. The OLE consisted of a 3-week blinded conversion phase (to 200 mg/day USL255), a 52-week open-label treatment phase, and a down titration of at least 3 weeks. USL255 dose adjustments of 50 mg/week were permitted after 11 weeks, until an optimal dose was achieved (maximum 400 mg/day); AED adjustments were also allowed following 11 weeks of treatment. Safety assessments included treatment-emergent adverse event (TEAE) monitoring.
RESULTS: Of the 217 patients who completed PREVAIL, 210 (96.8%) elected to continue into the OLE study. As of the interim cutoff date, approximately 33 months after study start, data were available for 209 patients: 91 (43.5%) completed the year-long study, 70 (33.5%) were continuing treatment, and 48 (23%) had discontinued. Mean and median drug exposure for all patients were 283 and 347 days, respectively. A total of 18 (8.6%) patients discontinued due to a TEAE. The most common TEAEs were decreased weight (7.2%), headache (7.2%), somnolence (7.2%), and dizziness (5.7%). A total of 13 patients (6.2%) had at least 1 serious adverse event; of those only cholelithiasis (n=2) and status epilepticus (n=2) occurred in more than 1 patient.
CONCLUSIONS: Interim exposure and safety data suggest that USL255, at dosages up to 400 mg/day, is generally well tolerated as an adjunctive treatment for refractory partial-onset seizures.
Study Supported by: Upsher-Smith Laboratories, Inc.

Category - Epilepsy and Clinical Neurophysiology (EEG): Therapeutics: Medical

Tuesday, April 29, 2014 3:00 PM

P3: Poster Session III: Epilepsy and Clinical Neurophysiology: AED (3:00 PM-6:30 PM)


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